Method for molding a concrete railroad tie

ABSTRACT

A CONCRETE POURING FORM ACCESSORY SUPPORTS A SLIDABLY REMOVABLE SLEEVE AND INSERT THREADED THERETO IN A MOLD OR POURING FORM DURING POURING OF A CONCRETE RAILROAD TIE. FOLLOWING HARDENING OF THE RAILROAD TIE, THE TIE IS READILY SLIDABLY REMOVED FROM THE SUPPORT POST THEREBY LEAVING THE SLEEVE INSERTED WITHIN THE INSERT TO PROTECT THREADS OF THE INSERT UNTIL THE SLEEVE HAS BEEN UNSCREWED FROM THE INSERT AT THE TIME OF BOLTING RAILS TO THE RAILROAD TIE. A RESILIENT ANNULAR CONE-SHAPED SEALING ELEMENT FORMS A PLUG BEHIND THE INSERT AND SLEEVE TO PRECLUDE THE APPLICATION OF BLOCKING CONCRETE BEHIND THE SLEEVE AND THE SUPPORT POST.

Jan. 19, 1971 E. L. KOWELL METHOD FOR MOLDING A CONCRETE RAILROAD TIE 2 Sheets-Sheet 1 w Filed March 27, 1968 INVENTOR. Edward L. Kowell a; 99 Horneys Jan. 19, 1971 E. KOWELL METHOD FOR MOLDING A CONCRETE RAILROAD TIE Filed March 27. 1968 2 Sheets-Sheet 2 Fig.5

INVENTOR. Edward L. Kowell 15w W Attorneys United States 1 Patent O 3,557,274 METHOD FOR MOLDING A CONCRETE RAILROAD TIE Edward L. Kowell, Greenbrae, Califi, asslgnor to H. Pomeroy & Company, Inc., San Francisco, Cal1f., a corporation of California Filed Mar. 27, 1968, Ser. No. 716,516 Int. Cl. B28b 13/06 US. Cl. 264--275 2 Claims ABSTRACT OF THE DISCLOSURE A concrete pouring form accessory supports a slidably removable sleeve and insert threaded thereto in a mold or pouring form during pouring of a concerte railroad tie. Following hardening of the railroad tie, the tie 1s readily slidably removed from the support post thereby leaving the sleeve inserted within the insert to protect threads of the insert until the sleeve has been unscrewed from the insert at the time of bolting rails to the railroad tie. A resilient annular cone-shaped sealing element forms a plug behind the insert and sleeve to preclude the application of blocking concrete behind the sleeve and the support post.

BACKGROUND OF THE INVENTION ploy prestressing elongated tendons carried under tension therein.

SUMMARY OF THE INVENTION AND OBJECTS As disclosed herein, a concrete pouring form accessory has been provided for casting concrete products containing an anchored insert embedded in the concrete. The accessory comprises a support post adapted to be carried by a pouring form in a manner so as to project inwardly of a wall portion of the form. A protective sleeve formed with positive engagement portions, such as exterior threads formed around the outside of the sleeve, is slidably positioned onto the distal end of the support post. An anchor element of a type adapted to receive and hold bolts to be coupled or threaded thereto when embedded in concrete is carried by the sleeve mounted on the post. Thus, the anchor element is carried in readily releasable positive engagement with the sleeve whereby unscrewing the sleeve from the anchor element serves to expose the threads for use with bolts of a type adapted to attach railroad rails to the ties.

Each anchor element is, in general, provided with laterally protruding portions which serve to develop a positive holding anchored engagement with concrete upon hardening of the concrete in which it is submerged. Thus, a flange is formed about the anchor element. Further, means are carried by the support post which serve to preserve sufficient clearance axially behind the sleeve and behind the post which is effective during placement of concrete poured about the accessory to preserve the ready removal path of the post from the sleeve and also later the sleeve from the insert.

In addition, the invention contemplates a cooperative disposition of certain of the anchored insert elements with respect to tensioned tendon members in the tie whereby restraint against axial movement of the embedded insert elements is partially derived directly from the tensioned tendon elements.

It is an object of the invention to provide an improved method of forming a precast concrete railroad tie.

This and other objects of the invention will be more 3,557,274 Patented Jan. 19, 1971 ice readily apparent from the following detailed description, when taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 and 2 are respectively plan and side elevation views of a railroad tie formed according to the invention.

FIGS. 3 and 4 are respectively enlarged elevation section views taken along the line 33 and 4-4 respectively.

FIG. 5 is a schematic end view, in section, showing a pouring form accessory according to the invention.

FIG. 6 is an enlarged, exploded, isometric view of a pouring form accessory according to the invention.

FIGS. 7 and 8 are each transverse end section views showing a concrete product according to the invention respectively in a state immediately following removal from the pouring form shown in FIG. 5 and shown in position ready to receive the application of rails thereto FIG. 9 is an enlarged elevation section view of a central portion of the casting accessory assembly 28.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 1 and 2, a concrete railroad tie 10 of a type employing prestressing tensioned tendons 1'1, 12, 13, 14 includes molded or cast portions for supporting railroad rails and ballast portions adapted for contact signal supports. Thus, the mutually inwardly and downwardly sloping rail pad portions 16 are adapted to receive the lower flanges of railroad rails (not shown) in conventional fashion for attachment by means of threaded bolts (not shown) which cooperate with interiorly threaded inserts 17 embedded in the concrete. Additional inserts 18 embedded in the concrete in a ballast zone 19 serve to cooperate with the threaded ends of bolts em ployed for attachment of additional railroad equipment in the form, for example, of the contact signal type.

From the foregoing, it will be readily apparent that each of inserts 17, 18, as embedded in the concrete of the body of railroad tie 10 form anchoring points of attachment with the tie 10 for coupling forces acting along the axis of the inserts 17, 18 to the body of concrete.

In order to enhance and derive improved holding action and thereby increase the restraint with which the concrete of each tie 10 holds inserts 17, which are subjected to the great forces applied by trains travelling on rails supported upon pad portions 16, it has been found advantageous to dispose tendons 12, 13 relatively close adjacent the sides of inserts 17. Thus, tendons 12, 13 have been disposed relative to inserts 17 in a manner whereby a pair of parallel planes 21, '22, disposed parallel to the axis of inserts 17 and respectively spaced laterally in a common direction from the axis of inserts 17 may be defined on each side of the inserts 17. The parallel planes thus respectively lie contiguous to the bounding adjacent portions of tendons 12 or 13, respectively and inserts 17. The spacing 23 between the parallel planes 21, 22 is sufiiciently narrow so as to cause the tendon 12 to contribute restraint to the axial movement of inserts 17 in the body of concrete under application of forces to the inserts, as by means of the applied forces experienced by trains carried on the rails thus supported.

In the method of forming the precast concrete railroad tie bodies, a frame, such as the box-like structure 24, open along the top, serves to hold a wooden pouring form 26 or mold of a type suitable for receiving the mixed concrete. Tendons 11, 12, 13 and 14 are supported by conventional means in each of the opposite end walls 27 of the pouring form structure.

A concrete pouring form accessory in the form of the casting assembly 2-8 serves to provide the concrete tie 10 with an embeded insert formed with female threads 29 for positively engaging the threaded end of a bolt, of a type as conventionally utilized in applying rails to pads 16. The threads 29 of each insert 17 are further provided in a manner whereby they remain sealed from exposure to damaging influences whereby at the point of utilization the threads are otherwise clogged or rusted, or otherwise damaged.

Thus, a mounting post 31 is carried to project inwardly from the wall 32 of pouring form 26. An exteriorly threaded antifn'ction sleeve 33 threadedly engages the interior threads 29 of the annular insert 17. Sleeve 33 includes a smooth interior bore 34 for slidably positioning sleeve 33 onto the upper end portion 31a of post 31. Preferably, sleeve 33 consists of an antifriction material such as various known plastics in order to facilitate the ready removal from post 31.

While only a single post 31 has been described above, it will be evident that a number of such mounting posts 31 shall be utilized in cooperation with the other inserts 17, 1'8, and the provision of anti-friction sliding relation between the interior of sleeves 33 and the exterior of post portions 31a can serve to aid in the releasing of each precast tie 10 from pouring form 26.

Post 31 includes an enlarged portion 3112 serving to carry an annular resilient truncated cone element 37 surrounding post 31 and adapted to be coated with an application of anti-bonding material such as grease in order to provide ready removal thereof from the hardened concrete product.

Element 37 serves to define access passages 36 behind sleeve 33 and, together with post portion 31b, serves to define the access passage behind post portion 31a whereby the post portion 31a may be readily withdrawn from the concrete body upon hardening of the concrete.

Accordingly, it will be readily apparent that element 37 and post portion 31b serve to preserve sufiicient clearance axially behind sleeve 33 and post portion 31a during placement of concrete so as to permit ready removal, first of the post from the sleeve, and later of the sleeve from tie 10.

After post 31 has been loosely secured to the wall 32 of form 26, as by means of the nut 38 and washer 39, sealing element 37 is slidably positioned onto post portion 31b. The insert 17, carrying sleeve 33 threaded thereto, is slidably placed onto the smooth cylindrical upper post portion 31a. Sleeve 33 includes a closed end portion 33a whereby the inner end of insert 17 shall be sealed against entry of concrete. Subsequently, nut 38 is taken up tightly to draw post 31, and particularly the radially protruding flange portion 310 thereof tightly against the opposite side of wall 32. The skirt 40 of element 37, then compressed, forms a tight seal around the base of assembly 28.

The inner end of each insert 17 is formed with a radially outwardly projecting fiange portion 17a forming laterally protruding portions serving to develop a positive holding anchored engagement with the hardened concrete in which it is submerged. Having completed the foregoing steps, it is then only necessary to pursue the final steps of pouring hardenable concrete-forming material into mold form 26 while sealing the mold form at the outer end of the sleeve 33 and post 31 in a manner preserving the access clearance behind both of these elements for later backing them out of the body of concrete after it has hardened.

Subsequently, after permitting the poured material to harden, each tie body is pulled relatively away from the posts 31 to slidably remove the posts 31 from their respective sleeves 33. Sleeves 33 are left in place until the tie 10 is ready for use. At that time sleeves 33 are unscrewed from their respective inserts 17 in order to expose the interior threads 29 for attachment to suitable threaded bolts as employed for attachment to rails to be laid upon ties 10.

From the foregoing, it will be readily evident that there has been provided an improved concrete product formed with an attachment device of a type having female threads adapted to cooperate with the threaded ends of bolts or the like inserted thereto. The threads are continuously protected by a sealed plug until ready for use. The interior of the plug serves further the purpose of readily releasing the precast body of concrete from its pouring form. Thus, when the product is ready for use, it is a simple matter to merely drive a screwdriver into the plastic sleeve 33 and unscrew same from the insert 17 I claim:

1. In a method for forming a precast concrete railroad tie body, the steps including fixedly positioning a mounting post to project inwardly from a wall of a reusable form or mold of a type adapted to receive concrete therein to form the tie, applying an annular, interiorly threaded, anchor insert in threaded engagement with the threads of an exteriorly threaded anti-friction tubular sleeve, then slidably applying said tubular sleeve and insert onto said post, submerging the insert in hardenable concrete-forming material while sealing the mold form at the outer end of said sleeve and post in a manner preserving clearance behind both said sleeve'and post for backing same out of said body after the said material hardens and leaving the sleeve threaded to said insert, and permitting said material to harden, and thereafter moving the concrete body, insert and sleeve relatively away from the post to slidably remove the post from the sleeve.

2. In a method of forming a precast concrete railroad tie according to the steps of claim 1, the additional step of unscrewing the sleeve from the insert to expose the interior threads within the insert for attachment to rails to be laid thereon.

References Cited UNITED STATES PATENTS 1,323,067 11/1919 Keith 25131 2,305,252 12/1942 Hayden 2513l 2,366,401 1/1945 Haskell 249-91X 3,445,559 5/1969 Siteman 264-278X 3,471,118 10/1969 Bormann 2499l FOREIGN PATENTS 1,164,639 3/1964 Germany 264-94 ROBERT F. WHITE, Primary Examiner A. M. SOKAL, Assistant Examiner US. Cl. X.R. 264-278, 334 

